1. Field of the Invention
The present invention relates to portable circular saws.
2. Description of the Prior Art
In general, portable circular saws include a housing enclosing an electric motor therein, a handle carried by the housing, a circular saw blade operatively connected to the electric motor, a blade case fixed to the housing and adapted to enclose substantially the upper half of the saw blade, a base plate for supporting the housing thereon, and a safety cover pivotally mounted on the housing and adapted to cover substantially the lower half of the saw blade projecting from the base plate. In one common construction for such circular saws, the housing is mounted on the front and rear ends of the base plate for pivotal movement in both the longitudinal and transverse directions of the base plate. Thus, the amount of projection of the circular saw blade below the base plate may be adjusted and further, the tilt angle of the circular saw blade relative to the base plate may be adjusted. In some designs, the drive shaft of the motor is arranged in parallel to the circular saw blade, and the handle is located at the rear portion of the whole saw.
In any of the above described conventional circular saws, when it is desired to temporarily rest the saw on a work site or the like in practice, it must be supported on a side edge of the base plate and the safety cover covering the lower half of the circular saw blade projecting from the base plate. While the circular saw is in its rest position, the base plate is transversely tilted, or the saw body is transversely tilted.
In many cases, however, the portable circular saw is operated to cut a workpiece with the base plate held upright with respect to the horizontal plane. If the operation is completed by a single cut, no problem will be caused in the operating performance of the circular saw which is set in the transversely tilted rest position as mentioned above. However, when several continuous cutting operations are performed, a series of actions have to be repeated, which includes gripping the handle, raising up the saw body from the tilted rest position to the upright position to cut a workpiece and, after cutting the workpiece, replacing the saw body to the transversely tilted position. In particular, the action of raising up the saw body from the transversely tilted rest position to the upright position has to be repeated at every cutting operation, thus reducing the efficiency in use.
Further, when the safety cover pivotally covering the circular saw blade is rested on a work site as described above, the safety cover may be unexpectedly pivoted to expose the cutting edge of the circular saw blade, thereby resulting in a serious accident.